End effects and cross-dimensional interference in identification of time and length: Evidence for a common memory mechanism

Number-time interaction: Search for a common magnitude system in a cross-modal setting

A theory of magnitude (ATOM) suggests that a generalized magnitude system in the brain processes magnitudes such as space, time, and numbers. Numerous behavioral and neurocognitive studies have provided support to ATOM theory. However, the evidence for common magnitude processing primarily comes from the studies in which numerical and temporal information are presented visually. Our current understanding of such cross-dimensional magnitude interactions is limited to visual modality only. However, it is still unclear whether the ATOM-framework accounts for the integration of cross-modal magnitude information. To examine the cross-modal influence of numerical magnitude on temporal processing of the tone, we conducted three experiments using a temporal bisection task. We presented the numerical magnitude information in the visual domain and the temporal information in the auditory either simultaneously with duration judgment task (Experiment-1), before duration judgment task (Experiment-2), and before duration judgment task but with numerical magnitude also being task-relevant (Experiment-3). The results suggest that the numerical information presented in the visual domain affects temporal processing of the tone only when the numerical magnitudes were task-relevant and available while making a temporal judgment (Experiments-1 and 3). However, numerical information did not interfere with temporal information when presented temporally separated from the duration information (Experiments-2). The findings indicate that the influence of visual numbers on temporal processing in cross-modal settings may not arise from the common magnitude system but instead from general cognitive mechanisms like attention and memory.

Cross-dimensional magnitude interactions reflect statistical correlations among physical dimensions: Evidence from space-time interaction

Magnitudes of different physical dimensions have been assumed to be processed by a common metric in order to account for interactions between different dimensions (e.g., space, time). This paper tested a different hypothesis, that these cross-dimensional interactions reflect people's experience of statistical correlations among physical dimensions. In the experiment, we manipulated the correlation between space (length) and time (duration). A stimulus consisting of two vertical bars that demarcated a variable stimulus length was presented for a variable stimulus duration; participants were to reproduce either the stimulus length or the stimulus duration. Critically, to reproduce a stimulus length, participants held down the spacebar to grow or shrink (in a blocked design) a length to the stimulus length such that space (i.e. reproduced length) positively or negatively co-varied with time. Reproduced lengths did not vary as a function of stimulus duration under positive space-time correlation but decreased as a function of stimulus duration under negative space-time correlation; reproduced durations increased as a function of stimulus length under positive space-time correlation but this space-on-time effect appeared to be attenuated under negative space-time correlation. These findings are consistent with a Bayesian inference account whereby cross-dimensional interactions reflect people's prior belief/knowledge of cross-dimensional statistical correlation, which itself tunes to recent input.

Cross-dimensional magnitude interaction is modulated by representational noise: evidence from space-time interaction

Magnitudes along different dimensions (e.g., space and time) tend to interact with each other in perception, with some magnitude dimensions more susceptible to cross-dimensional interference than others. What causes such asymmetries in cross-dimensional magnitude interaction is being debated. The current study investigated whether the representational noise of magnitudes modulates the (a)symmetry in space-time interaction. In three experiments using different formats of length, we showed that dynamic unfilled lengths resulted in a higher representational noise than either static unfilled length or static filled length. Correspondingly, we observed that the time-on-space effect was larger for dynamic unfilled lengths than for static unfilled length or static filled length (and it did not differ between the latter two). Further correlational analyses showed that the susceptibility of a target dimension to the influence of a concurrent dimension increased as a function of participants' representational noise in the target dimension (e.g., the noisier length representations, the larger the time-on-space effect). In all, our study showed that the representational noise of space and time modulates the way the two dimensions interact. These findings suggest that cross-dimensional magnitude interactions arise as a result of memory interference, with noisier magnitudes being more prone to being nudged by concurrent magnitudes in other dimensions. Such memory interference can be seen as a result of Bayesian inference with correlated priors between magnitude dimensions.

Comparative inspiration: From puzzles with pigeons to novel discoveries with humans in risky choice

Both humans and non-human animals regularly encounter decisions involving risk and uncertainty. This paper provides an overview of our research program examining risky decisions in which the odds and outcomes are learned through experience in people and pigeons. We summarize the results of 15 experiments across 8 publications, with a total of over 1300 participants. We highlight 4 key findings from this research: (1) people choose differently when the odds and outcomes are learned through experience compared to when they are described; (2) when making decisions from experience, people overweight values at or near the ends of the distribution of experienced values (i.e., the best and the worst, termed the "extreme-outcome rule"), which leads to more risk seeking for relative gains than for relative losses; (3) people show biases in self-reported memory whereby they are more likely to report an extreme outcome than an equally-often experienced non-extreme outcome, and they judge these extreme outcomes as having occurred more often; and (4) under certain circumstances pigeons show similar patterns of risky choice as humans, but the underlying processes may not be identical. This line of research has stimulated other research in the field of judgement and decision making, illustrating how investigations from a comparative perspective can lead in surprising directions.

On magnitudes in memory: An internal clock account of space-time interaction

Traditionally, research on time perception has diverged into a representational approach that focuses on the interaction between time and non-temporal magnitude information like spatial distance, and a mechanistic approach that emphasizes the workings and timecourse of components within an internal clock. We combined these approaches in order to identify the locus of space-time interaction effects in the mechanistic framework of the internal clock model. In three experiments, we contrasted the effects of spatial distance (a long- vs. short-distance line) on time perception with those of visual flicker (a flickering vs. static stimulus) in a duration reproduction paradigm. We found that both a flickering stimulus and a long-distance line lengthened reproduced time when presented during time encoding. However, when presented during time reproduction, a flickering stimulus shortened reproduced time but a long-distance line had no effect. The results thus show that, while visual flickers affects duration accumulation itself, spatial distance instead biases the memory of the accumulated duration. These findings are consistent with a clock-magnitude account of space-time interaction whereby both temporal duration and spatial distance are represented as mental magnitudes that can interfere with each other while being kept in memory, and places the locus of interaction between temporal and non-temporal magnitude dimensions at the memory maintenance stage of the internal clock model.